Hack: Incomplete impl. for Dot3RGBA combiner operation.

src/video_core/pica.h

@@ -261,7 +261,8 @@ struct Regs {
             AddSigned       = 3,
             Lerp            = 4,
             Subtract        = 5,
-
+            Dot3RGB         = 6,
+            Dot3RGBA        = 7,
             MultiplyThenAdd = 8,
             AddThenMultiply = 9,
         };

src/video_core/rasterizer.cpp

@@ -3,6 +3,7 @@
 // Refer to the license.txt file included.
 
 #include <algorithm>
+#include <numeric>
 
 #include "common/common_types.h"
 #include "common/math_util.h"
@@ -439,6 +440,16 @@ static void ProcessTriangleInternal(const VertexShader::OutputVertex& v0,
                         return result.Cast<u8>();
                     }
 
+                    case Operation::Dot3RGBA:
+                    {
+                        //return std::inner_product(begin(a), end(a), begin(b), 0.0);
+                        int a[] = { input[0].r(), input[0].g(), input[0].b() }; //int a[] = { 1, 3, -5 };
+                        int b[] = { input[1].r(), input[1].g(), input[1].b() };
+
+                        auto res = std::inner_product(a, a + sizeof(a) / sizeof(a[0]), b, 0);
+                        return{ res, res, res };
+                    }
+
                     case Operation::MultiplyThenAdd:
                     {
                         auto result = (input[0] * input[1] + 255 * input[2].Cast<int>()) / 255;
@@ -482,6 +493,9 @@ static void ProcessTriangleInternal(const VertexShader::OutputVertex& v0,
                     case Operation::Subtract:
                         return std::max(0, (int)input[0] - (int)input[1]);
 
+                    case Operation::Dot3RGBA:
+                        return 255;
+
                     case Operation::MultiplyThenAdd:
                         return std::min(255, (input[0] * input[1] + 255 * input[2]) / 255);